Build anywhere:
During game play, enter the options menu and select "Interface". Set North to "8", East to "6", West to "4", and South to "4" on the keypad. Resume the game and construct something. Take the building, and when you get an all white outline, click and hold down the mouse as if you want to place it down, but do not release the mouse button. Move the cursor over the build panel (far right) and using the number keys 2, 4, 6, 8, move to where you want to place your building. Then, release the mouse button and deploy your building under the menu panel. This may take a few tries but is does work.

Firestorm defense:
Play as the GDI. If your enemy likes air units or missiles, surround your base with the Firestorm Wall at a distance from your base, backed up with RPG Launchers. Whenever aircraft or missiles are detected coming toward you, turn the Firestorm on. When aircraft attack, wait until just before they cross the Firestorm line so that they cannot turn away before they are hit. Do not worry if the Firestorm is attacked by the enemy aircraft -- it is pretty tough. Just bring some MRLS in to assist destroying the aircraft.

Cyborg Reaper:
Build a Cyborg Reaper and send it to the enemy's base. Walk on Tiberium and stay there. The enemy will shoot at it, but the Tiberium will heal it quickly.

Unlimited Firestorm:
Precise timing is required for this trick. Build a Firestorm generator. When it is ready, click to activate it, and blow it up as soon as it becomes activated. This works best if you have a Ghost Stalker. Have the Ghost Stalker place C4 on the generator, then when it flashes, quickly turn it on and it will automatically explode. The game will be fooled into thinking that you still have the generator. You can turn it off by building another generator and re-clicking on the Firestorm button.

Drop Pods:
When fighting the GDI you may hear machine guns firing. This is normal because those sounds were just Drop Pods. The Drop Pods have people in them that have gold stars (which indicates that they are very good).